With the proliferation of PCs and advances in computer technologies, there has been a demand for PCs that have an increasing number of advanced features. Customers that purchase multimedia PCs and high-end gaming PCs in particular are demanding premium audio quality in order to achieve the ultimate audio/visual experience from their PCs. This demand has been addressed to some extent by the HDA specification introduced by Intel.
When Intel's 1997 Audio Codec standard (AC'97) was introduced, PC users typically listened to music and movies that only had stereo sound. As multi-channel audio formats such as Dolby Digital and DTS became more popular, users became accustomed to these audio formats and began to expect full surround, multi-speaker sound using these formats to be available in a PC environment. While AC'97 technology was initially adequate, it has not been able to keep pace with more recent advancements (e.g., newer audio and video encoding/decoding algorithms) that enable the PC to produce higher-quality audio.
Beginning with the introduction of Intel's High Definition Audio Specification Rev 1.0 in 2004, which is incorporated herein by reference, the HDA interface has been gradually gaining popularity in the PC space. The HDA architecture defined by the Intel specification attempts to meet the need for high quality audio in the PC space. This architecture defines the delivery of high fidelity audio content from a PC's memory to one or more audio codecs using an HDA controller that performs direct memory access (DMA) transfers of audio data over an HDA bus. The audio data delivered over the HDA bus is received, processed and output by the various components of the codecs (referred to in the HDA specification as “widgets”).
While the HDA specification allows quite a bit of flexibility in the design of an HDA system for a PC, this flexibility is lost when the design is implemented. For instance, while an HDA system may have multiple codecs that perform different types of processing on audio data, these codecs are hardwired and their functionality cannot be changed.